Answer:
The temperature must be -49.5°C
Explanation:
A helium balloon has a volume of 500 mL (=0.5L) at stp this means 25°C and 1atm
In this situation, the volume is increased to 750 mL (= 0.750L) and the pressure decreased to 0.5 atm
For this situation we will use the following formula:
(P1 * V1)/T1 = (P2 * V2) /T2
with P1 = initial pressure = 1atm
with V1 = the initial volume = 0.5 L
with T1 = the initial temperature = 25°C = 298.15 Kelvin
with P2= The changed pressure = 0.5 atm
with V2 = The changed volume = 0.750 L
with T2 = The changed temperature = TO BE DETERMINED
(P1 * V1)/T1 = (P2 * V2) /T2
(1atm *0.5L)/298.15 K = (0.5 atm * 0.750 L) / T2
T2 = 223.6 Kelvin = -49.5 °C
The temperature must be -49.5°C
